I have a comp. I build last year and was thinking of adding another GPU. My question is this I have a asus p5k mobo and a asus 4870 gpu with 512mb and I'm unable to find the exact model, dunno why. So can I get another 4870 gpu by asus or another manufacturer with the same 512 or 1 gb and crossfire or is this not suggested. I'll try and find the exact mobo I bought last year and post, I bought it from newegg so maybe I can pull up past invoices?